In U.S. elections, when someone shows up at a polling place to cast a vote, but is not on the list of people who may vote there (is not registered in that precinct, or his registation is otherwise invalid or inaccurate), he may be allowed to cast a provisional ballot. The eligibility of the voter is then verified after the election, and, if it is found that he was eligible to vote, his vote is then counted as an ordinary ballot.

A guarantee that a voter could cast a provisional ballot if he believes that he is entitled to vote was one of the guarantees of the Help America Vote Act of 2002.